How many links does it take…….

[Cpd419]

To Fit on a 22 trail with a 13 tooth front sprocket?

 

[dmonkey]

The stock length of 108 links works and lets you switch between 13T and 14T should you want to.

 

[Cpd419]

I guess what I meant was what’s the least number of links required for a 13 tooth. It may be a hard question to answer.

 

[AZ7000']

I guess what I meant was what’s the least number of links required for a 13 tooth. It may be a hard question to answer.

13????

 

[SneakyDingo]

13????

12.5, since one of them would have to be a half link

 

[SneakyDingo]

Short answer: 106 links, maybe under really extenuating circumstances 104 links.

I want to know "why" you want to fit a smaller number of links. The first thing that comes to mind is you've cut the chain too short (use 2 master links and don't think about it, or buy a new chain), and the second is you're trying to buy a shorter length of chain than the 108 links that is specified? Neither of those being amazingly good reasons but to each their own I guess.

Math:
I looked at my swingarm today and I can move my chain forward ~20mm remaining space on my 2021 (Red). The chain is a 428 chain with a 0.5" pitch, 14T on the front and a 39T on the back. The center of the chain would approximate a circle, good enough for estimation calculations, so you can use pi*D = (# of teeth * 0.5 inches) to get the diameter of the cog in inches. That allows for my motorcycle's front sprocket, rear sprocket and 108 link chain to be approximated with this diagram:



Where units are in inches (approximate because wear on the chain, path of the chain isn't exactly circular, etc. but it should be accurate within ~3%).

Changing that front sprocket to a 13T, keeping the 39T on the back, and shortening the center-to-center of the cogs length by 20mm results in:



The resulting chain length is 52.2 inches. Because we know this is a 428 chain with a half inch pitch, and that chains are one outer plate link and one inner plate link, you have to remove multiples of 2 links unless you are using a half link, which we will assume you do not have. Thus each pair of links is 1 inch. So you need the mathematical ceiling calculation of 52.2 * 2 = 104.4 links, rounded up to the nearest 2 links, or the result of 106 links is the minimum you can run. Of course, if you run the chain tight, if you're a light rider only on flat ground, and you have like... 26mm of axle movement available to you since I approximated as I didn't want to undo my rear axle nuts, you can probably swing 104 links.

This approximated what I expected without running calculations. Every time you remove 2 links, you're shortening the rear swingarm 0.5 inch since there's a top and bottom section of chain that is effectively becoming shorter. It's approximate because the relationship to the swingarm (horizontal dashed line) and the chain (solid line on top and bottom) isn't 1:1 due to the sprockets being different sizes. With only 20mm of movement available, you're only going to be able to move that approximately half an inch.

 

[Little_Thumper_Boy]

Short answer: 106 links, maybe under really extenuating circumstances 104 links.

I want to know "why" you want to fit a smaller number of links. The first thing that comes to mind is you've cut the chain too short (use 2 master links and don't think about it, or buy a new chain), and the second is you're trying to buy a shorter length of chain than the 108 links that is specified? Neither of those being amazingly good reasons but to each their own I guess.

Math:
I looked at my swingarm today and I can move my chain forward ~20mm remaining space on my 2021 (Red). The chain is a 428 chain with a 0.5" pitch, 14T on the front and a 39T on the back. The center of the chain would approximate a circle, good enough for estimation calculations, so you can use pi*D = (# of teeth * 0.5 inches) to get the diameter of the cog in inches. That allows for my motorcycle's front sprocket, rear sprocket and 108 link chain to be approximated with this diagram:

View attachment 6478

Where units are in inches (approximate because wear on the chain, path of the chain isn't exactly circular, etc. but it should be accurate within ~3%).

Changing that front sprocket to a 13T, keeping the 39T on the back, and shortening the center-to-center of the cogs length by 20mm results in:

View attachment 6479

The resulting chain length is 52.2 inches. Because we know this is a 428 chain with a half inch pitch, and that chains are one outer plate link and one inner plate link, you have to remove multiples of 2 links unless you are using a half link, which we will assume you do not have. Thus each pair of links is 1 inch. So you need the mathematical ceiling calculation of 52.2 * 2 = 104.4 links, rounded up to the nearest 2 links, or the result of 106 links is the minimum you can run. Of course, if you run the chain tight, if you're a light rider only on flat ground, and you have like... 26mm of axle movement available to you since I approximated as I didn't want to undo my rear axle nuts, you can probably swing 104 links.

This approximated what I expected without running calculations. Every time you remove 2 links, you're shortening the rear swingarm 0.5 inch since there's a top and bottom section of chain that is effectively becoming shorter. It's approximate because the relationship to the swingarm (horizontal dashed line) and the chain (solid line on top and bottom) isn't 1:1 due to the sprockets being different sizes. With only 20mm of movement available, you're only going to be able to move that approximately half an inch.

Nice work, Sneaky!

 

[Cpd419]

I bought a chain cut too short but with my 13 tooth sprocket it works with the right amount of slack and one master link. The wheel is far forward but it is tracking straight and plenty of slack and the o-ring chain is way smoother. Power is the same as far as I can tell. And I counted 52 big links not counting the master just fyi.

 

[SneakyDingo]

I think the only worry I'd have is the chain binding because it's too short.

 

[m in sc]

as long as the freeplay is withing spec should be good to go.

 

[Cpd419]

I think the only worry I'd have is the chain binding because it's too short.

Not at all. It’s super smooth. Way more than the oem chain. I ran it without the side cover and watched it for awhile before I buttoned it up.